The North and South Poles were dubbed "climatic bellwethers" when
scientists first began studying global trends. Most climate models predict that
if global temperatures are going to change, the change will be noticed first
at the Poles. The models show amplified warming, as has been observed in Arctic
regions and parts of Antarctica over the last half of the 20th century. Scientists
are keenly aware of the importance Antarctica plays in climate studies and have
been diligently watching for any changes or trends.

Over the course of two weeks, three seemingly contradictory reports were published.
One says that indeed, the frozen frontier is warming; one says that the continent
is actually cooling; and one says an ice sheet is thickening rather than melting.
So what is the real story?

First and foremost, it is important to note that all of the articles and the
scientists involved agree on one thing: "We're not saying anything close
to 'the Earth's climate is not warming,'" as an animated Peter Doran of
the University of Illinois at Chicago puts it.

The second important conclusion they all draw: much more research is needed.
Whatever the length of time each scientist has been studying Antarctica, it
pales in comparison to the length of time needed to draw any universal conclusions.

As reported in the Jan. 25 Science, Wendy Quayle and Lloyd Peck of the
British Antarctic Survey led a team that has been measuring the decline in summer
ice cover on freshwater lakes on Signey Island near the Antarctic Peninsula.
The lakes, frozen solid through the harsh Antarctic winter, have warmed significantly,
dramatically altering the ecosystem. The lakes are ice-free for an average of
31 days per year longer compared with fifteen years ago. Over the past 20 years,
the air temperature has increased by nearly 2º Fahrenheit on the island.

Working on the other side of the continent, Peter Doran led researchers with
the National Science Foundation's Long Term Ecological Research (LTER) team
studying temperature changes and subsequent effects on the ecosystem in the
Dry Valleys near McMurdo Sound, as reported in the online January Nature.

"We found that over the past 35 years, more of the continent has been
cooling than warming, and the cooling has been about 1º F decrease per
decade in the Dry Valleys since 1986," Doran says. He insists Quayle and
Peck's findings do not contradict his study; his study shows that while the
Dry Valleys are cooling much faster than the rest of the continent, areas such
as the Antarctic Peninsula are warming faster. The LTER scientists' analysis
indicates that overall, 58 percent of the continent is cooling.

To the west of McMurdo Sound lies the West Antarctic Ice Sheet, which has been
retreating during this entire interglacial period. As Ian Joughin of NASA's
Jet Propulsion Laboratory and Slawek Tulaczyk of the University of California
at Santa Cruz write in their article in the Jan. 18 Science, part of
the ice sheet has actually begun to thicken, not melt.

"Due to a 10,000 year thinning, this part of Antarctica was believed to
be subject to a large breakup," Joughin explains. "As part of the
ice sheet is actually thickening, the long-term retreat may be coming to an
end and the potential risk of collapse may be significantly smaller than previously
believed."

The West Antarctic Ice Sheet is thickening because a few of its ice streams
- Antarctica's glacial equivalent of rivers - have been damming up for 200 years,
causing a backup that is continually growing.

But Tulaczyk is quick to point out, "our results do not indicate that
the whole Antarctic Ice Sheet is growing, merely that 5-6 percent of the ice
sheet is currently thickening, and there is no direct causal link between these
ice sheets thickening and temperature increase or decrease."

Doran cautions: "All the continents on Earth are warming except Antarctica,
which could be just a delayed response. Our 35-year trend analysis highlights
the heterogeneous nature of the trends in Antarctica, and the models need to
catch up to match the mixed signals."

Tulaczyk agrees. "Climate models need to be improved to explain cooling.
They do not currently account for spatial or temporal variabilities such as
cooling. And these new aspects of ice-sheet behavior need to be incorporated
into glaciological models of ice-sheet flow."

The real story, as Doran puts it, is that Antarctica is the most data sparse
continent on Earth; much more research and a lot more time is needed. These
are processes that occur over thousands of years and these measurements only
represent a few years.